Strabismus, sometimes referred to as “lazy eye,” is a medical condition of the eye normally treated by disabling or otherwise interfering with the vision of the strong eye so that the patient will be forced to use the “lazy” one. Although the current treatments for Strabismus (chemically paralyzing, numbing or blocking the strong eye with an opaque patch) are unpleasant and, consequentially, irregularly applied, they can be effective if they are used consistently. Their effectiveness as a normative treatment for Strabismus appears to be related to the brain's ability, under external duress, to recognize and correct certain factors that result in poor vision.
Autism, a pervasive developmental disorder recognizable by physical rigidity, emotional detachment and impaired communication is both a major and a growing threat to children. According to a study published in Pediatrics, l Oct. 5, 2009, based on a National Children's Health Survey done with 78,000 parents in 2007, 1 percent of the population of children in the U.S. ages 3-17 have an autism spectrum disorder. It is also the fastest growing developmental disability (10-17% annual growth) according to an Autism Society estimate based on 2003 US state educational data.
Both disorders are especially prevalent in children, desperately need early diagnosis for a successful outcome and share a dearth of effective treatments whose side effects, discomfort, tedium and cosmetic disincentives to compliance do not require more patience and social confidence than this young and already emotionally challenged population can live up to.
Eye-tracking is a broadly used technology to determine the vision axes of the eyes. Then, responsive to their position and orientation, it can be determined essentially where the subject is looking. There are a wide variety of technologies for tracking the vision axis of each eye, all of which are applicable to the current invention.
For example, Mason in U.S. Pat. No. 3,462,604 on Aug. 19, 1969 uses an oculometer (a device that records the differences in electrical charge between the front and back of the eye. This can then be correlated with eyeball movement).
Graf in U.S. Pat. No. 4,109,145 issued Aug. 22, 1978 uses an oculometer or any other line of sight determining device and measures the length of static fixation. If the time of fixation passes a threshold value, the apparatus produces a control output (it's considered a valid fixation rather than an unintentional saccade).
U.S. Pat. No. 3,724,932 issued to Cornsweet et al. Apr. 3, 1973 uses a plurality of Purkinje images from the reflective surfaces of the eye. Monitoring the separation of the Purkinje images indicates the orientation of the optic axis of the eye.
U.S. Pat. No. 4,866,229 issued to Scharfenberg on Sep. 12, 1989 uses a heads-up display to track the eyes while the heads-up display is worn.
U.S. Pat. No. 4,651,145 issued to Sutter on Mar. 17, 1987 uses oculo-encephalographic signals captured responsive to unique coded signals presented to the subject with the EEG signal then used to determine where the subject is looking.
U.S. Pat. No. 5,293,187 uses electro-oculogram signals to control video devices.
Knapp et al. in U.S. Pat. No. 5,293,187, issued Mar. 8, 1994, which “relates generally to the operation of three-dimensional games and devices and strabismus measurement by determining the independent position of each eye” used an electrooculogram (electro-oculogram signals are, in effect, an electrical signature of eye movement that is not sensitive to ambient light interference) to determine eye position and to determine the horizontal and vertical position of each eye as well to determine convergence or divergence of the eyes. The signals representing eye position are interfaced to an output device for strabismus measurement. It is for diagnostic purposes only